Rivetless floating nut plates, are used in manufacturing applications where it is desirable to retain a nut on one side of a work piece in proximity to a countersunk hole through the work piece, so that a screw or other fastener can subsequently be installed from the countersunk side of the work piece to engage the nut. One use of rivetless nut plates is in constructing airplanes, such as the F-16 fighter plane. The rivetless nut plate commonly used in such aircraft applications is described in U.S. Pat. No. 4,732,518. Rivetless nut plates include a sleeve with a basket attached to one end, and an internally threaded nut is retained within the basket. A portion of the sleeve exterior, ajdacent the basket, is knurled. The knurled portion of the sleeve has an outer diameter sized for a friction fit inside a hole through the work piece and functions to prevent rotation of the nut plate assembly relative to the work piece once the assembly is installed. The sleeve length generally matches the thickness of the work piece, so that the smooth sleeve extends through the counter sunk hole but does not protrude beyond the work piece. When installed properly, the knurled portion of the sleeve is lodged inside the hole in the work piece, and the smooth end of the sleeve is flared to fit against the countersink of the hole.
Rivetless floating nut plates are usually attached to work pieces using a slow, cumbersome, two-step procedure. After the nut is screwed onto a mandrel, the nut plate assembly is pulled through the hole in the work piece until the knurled portion at the end of the sleeve engages the work piece inside the hole. Then, in a second step, the distal end of the sleeve is flared to fit tightly against the countersunk portion of the hole in the work piece. Several problems can arise during installation by this method. The sleeve may not be centered precisely within the hole in the work piece, resulting in an asymmetrical flaring of the distal end of the sleeve and poor retention of the sleeve within the hole in the work piece. With commonly used installation tools, such as a hand tool model no. TA7533, manufactured by Huck International, Inc., 3969 Paramount Boulevard, Lakewood, Calif. 90712, installation of rivetless nut plates is relatively slow, with as much as five to ten minutes required for an experienced technician to install each nut plate after the work piece is prepared to receive the fastener. This is due to the two-step procedure, where adjustment of the tool with respect to the tool's mandrel and the fastener sleeve length is very critical. If the installer selects the wrong relationship between the sleeve length and the mandrel, the fastener will not be properly installed and will need to be removed and replaced. If, for any reason, the mandrel and the sleeve are not centered properly in the hole, the knurled end of the sleeve may engage the wall of the hole in a way that the sleeve is not centered in the hole, which also results in a poor installation that may require removal and replacement of the fastener.